Inner tube for automobile tires



H. N. WAYNE. INNER TUBE FOR AUTOMOBILE TIRES. APPLICATION FILED AUG.2I,1920. RENEWED SEPT. 28. 1921.

Patented May 9, 1922.

. longitudinal as STATES PATENT INNER TUBE FOR AUTOMOBILE TIRES.

Specification of Letters Patent.

Patented May 9, 1922.

Application filed August 21, 1920, Serial No. 405,005. Renewed September28, 1921. Serial No. 503,928.

To all whom it may concern.

Be it known that I, HERBERT N. WAYNE, a citizen of the United States,residing .at Vashington, District of Columbia, have invented new anduseful Improvements in Inner Tubes for Automobile Tires, of which thefollowing is a specification.

This invention relates to inner tubes to carry air pressure insidepneumatic tires; and the general object of this invention is to providea means whereby the tube Wlll be rendered difficult of puncture; afurther object of the invention is to provide a means whereby the walls.of the tube may be reinforced and strengthened in degree proportionateto the varying requirements of different service conditions; it is alsoan object to .apply the reinforcing means in sucha manner as to allowall necessary expansibility in the tube along normal lines of expansionwhen the tube is inflated in a casing; it is also a further object toprovide an expa-nsible air-tube of such contour and construction as willbe best adapted to conform, without additional temporary expansion, tothe natural hinge of the tire due to the changing form of the tire wherethe casing comes in contact with the ground.

The constant flexing of the side walls of the casing at the point ofroad contact being the source of all frictional heat in the casing andinner tube.

The invention, its features, the manner of its construction and how itaccomplishes its objects, will be bestunderstood from the followingdescription, reference being had for this purpose to the accompanyingdraw- 1ngs Fig. 1 is a perspective view of a section of inner tubeconstructed in accordance with the invention.

Fig. 2 is a. perspective view of a modified form of construction of thetube.

Fig. 3 is a cross section of the improved tube.

Fig. 4: is a cross section of the improved tube as shown inflated withinthe casing.

Fig. 5 is a cross section view showing a depressed tire. in contact withthe ground.

Numbers 10 and 11 in Fig. 1 indicate strips of calendered fibrousmaterial having the longitudinal direction of the fibres in one striplying in diagonal relation to the direction of the fibres in the nextadjoining strip. Numbers 12 and 13 Fig. 2 indicate'fibrous materialapplied in in such a manner that two zones only, the longitudinaldirection of the fibres in. one zone (12) lying at right angles to thelongitudinal direction of the fibres in the other zone Number 14, Fig. 3indicates an arched bulge in the upper side wall of the tube for thepurpose hereinafter described. The dotted lines (15) indicate a modifiedform of construction hereinafter more fully described.

To accomplish the objects contemplated by my invention I prefer to use av mix of fibrous material. such as asbestos or vegetable fibre,preferably cotton, and rubber. I have successfully used such a mixcontaining 25% of ground cotton fibre and 75% of rubber and sulphur.

In constructing the tube I may first apply an inner lining of purerubber or other impervious material and then cover it with an outerlayer, or layers, of the fibrous compound. I wish to here note that inthe process of calendering a fibrous mixture or comound of the characterdescribed the short fibres of the shredded cotton are smoothed out in ageneral longitudinal direction as the mixture passes through and emergesfrom the calender rolls. The resulting sheet of fibrous mixture (orperhaps it is better to describe it by the usual technical namefibrecompound) will therefore possess a fibrous grain similar to the grainstructure of leather, also will in a large degree possess similarpuncture-proof qualities, and because the binder element is rubber, itfollows that such a sheet will be more elastic in transverse sectionthan it will be in longitudinal section of the sheet. a sheet whenvulcanized will offer much greater resistanceto any given degrees oftension force exerted upon it in a longitudinal direction than it willoffer to a similar force in the other or lateral direction. It is thesepeculiarities, variable elasticity and resistance to puncture, which arepossessed by In other words, such a suitably proportioned fibrouscompound,

inner tube. Realizing the importance ofmaking 'suitable provision forexpansion of the tube in all directions necessary to properly expand andfill the casing, I propose to lay varying layers of this fibrouscompound the direction of the grain in each layer will lie at adifferent angle than that of the next adjoining layer, from each other.

' tires,

In my preferred construction I divide the cross sectional circumferenceof the tube into two or more zones, each zone having a greater degree ofelasticity in one direction than in the other, with the-direction ofmaximum elasticity in one zone being in a different direction than theline of maximum elasticity in the next adjoining zone.

This may be accomplished by laying strips of calendered fibrous compounddiagonally in relation to the length of the tube, each alternate layerbeing laid at an angle different to the angle of the adjacent layer, asin Fig. 1 or the whole of the tread-portion may be covered by, or whollycomposed of, fibrous compound having the longitudinal direction of itsfibres running in a general transverse direction and the rim portioncovered by, or wholly composed of, fibrous compound having its fibresrunning in a general longitudinal direction, as in Fig. 2; a thirdmodification might to advantage combine both' previous modified forms.

Fig. 3 shows a cross section of the preferred contour of my improvedtube, the purpose of the arched bulges marked 14 in the drawing is tocause the tube at these points to follow the-natural elongation at theaxis of the bend caused by the flexing of the casing where it comes incontact with the ground, as illustrated in Fig. 6.

In the illustration Fig. 5'is shown the same tube as inflated withinthecasing under normal conditions.

To facilitate the emplacement of the tube within the casing I may moldthe tube with depression. circumferentially around its inner pheripheryas indicated by dotted lines 15 in Fig. 3, thereby raising this innercircumferential portion away from the rim and this reducing liability topinch the tube when the tire is mounted on the rim.

I havedescribed and illustrated my invention as especially applied toinner tubes, but-it is to be understood that, of course, the inventionis equally applicable to liners, reinforcements, etc., where thismaterial may be used.

Having described the various functions and methods of construction of myim proved inner tube, what I claim as new is 1. An inner tube forpneumatic tires conlongitudinal direction of the fibres in the nextadjoining zone.

2. An inner tube for pneumatic tires having a body portion composed offibrous material in mixed combination with rubber, the direction of thefibre being trans versely to the tube thus permitting expansionlongitudinally and restricting the expansion laterally.

3. An inneu tube comprising an inner lining of rubber; a layer ofcalendered fibrous material mixed with rubber and applied in two or morezones, the general direction, longitudinally of the fibres in one zone,lying at a different angle to the longitudinal direction of the fibresin the next adjacent zone, the whole being vulcanized to form a unitarystructure.

4:. In combination, a tire casing and an inner tube, the inner tubeconsisting of a body portion composed of an inner lining of soft rubbertube stock; a layer of calendered fibrous material mixed with rubbercovering the inner lining and applied in two or more zones, the generaldirection longitudinally of the fibres transversely of the tube,

the completed tube being vulcanized as a unitary whole.

5. In combination, a tire casing and an inner tube, the inner tubehaving longitudinally arched bulges circumferentially' of the tubearound the upper side walls;'a layer of soft rubber tube stock; a layerof calendered fibrous material mixed with rubber and appliedtransversely of the tube, and the completed tube being vulcanized as aunitary structure.

6. In combination, a tire casing and an inner tube, the inner tubehaving longitudinal arched bulges circumferentially of the tube; aninner lining of soft-rubber; an outer layer of fibrous material incombination mixed with rubber, the whole being vulcanized together as aunitary structure.

In testimony whereof I afiix my signa= I ture.

" HERBERT N. WAYNE.

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